1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device provided with a backlight which mounts a light guide plate on a back surface of a liquid crystal display panel.
2. Description of the Related Art
A liquid crystal display panel is configured to control transmissivity of liquid crystal in respective pixels and hence, the liquid crystal display panel usually mounts a backlight on a back surface thereof.
As such a backlight, there has been known a backlight which includes a light guide plate arranged substantially parallel to the liquid crystal display panel, and a light source such as a light emitting diode, for example, which is arranged to face at least one side wall surface of the light guide plate in an opposed manner.
In the liquid crystal display device having such a constitution, there has been a demand for the enhancement of brightness of image display of a liquid crystal display panel by directing light radiated from the liquid crystal display panel toward a viewer side.
When such a liquid crystal display device is used as a display device of a mobile phone, for example, the enhancement of property of focusing light from the liquid crystal display panel is preferable also from a viewpoint of protecting privacy of a display on the display device.
Accordingly, there has been known the constitution which arranges micro lenses between a backlight and a liquid crystal display panel, wherein the lenses are formed corresponding to respective pixels of the liquid crystal display panel. Due to such a constitution, light from the backlight is focused by the micro lenses and the focused light is incident on the liquid crystal display panel.
The liquid crystal display device having such a constitution is disclosed in JP-A-2005-275142 (patent document 1), JP-A-2005-62741 (patent document 2) or the like, for example.
Further, to enhance the visibility of a liquid crystal display device outdoors, there has been also proposed the conversion from transmissive liquid crystal which has been conventionally used in general in a liquid crystal display device to transflective liquid crystal. However, to compensate for lowering of brightness in a transmissive display mode using transflective liquid crystal, the enhancement of brightness is inevitable.
Further, cases that a television image is received by a personal digital assistant such as a mobile phone are increased in number and hence, the reduction of power consumption is inevitable for allowing a viewer to watch the television image for a long time.
However, in a liquid crystal display device having such a constitution, there has been a further demand for the enhancement of brightness of image display of the liquid crystal display panel by directing light from the backlight toward a viewer side. This is because an image display of high brightness can be realized in spite of low power consumption.